How do I take Coumadin or Warfarin?

  • Always follow the directions you are given.
  • Let all of your doctors and dentists know that you are on a blood thinner.
  • Because Coumadin dosages may change, it is recommend that you use a pill box with sections for each day of the week to ensure you take the medication correctly.
  • You should be familiar with the number of tablets you take and the color, name brand, and milligram strength.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:

  • back pain
  • chills
  • dizziness
  • fever
  • heavy menstrual bleeding or vaginal bleeding
  • painful, blue, or purple toes
  • painful, prolonged erection
  • signs and symptoms of bleeding such as bloody or black, tarry stools; red or dark-brown urine; spitting up blood or brown material that looks like coffee grounds; red spots on the skin; unusual bruising or bleeding from the eye, gums, or nose-skin rash, itching or skin damage
  • stomach pain
  • unusually weak or tired
  • yellowing of skin or eyes

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • diarrhea
  • hair loss

What if I miss a dose?

It is important not to miss a dose. If you miss a dose, call your healthcare provider. Take the dose as soon as possible on the same day. If it is almost time for your next dose, take only that dose. Do not take double or extra doses to make up for a missed dose.

What can interact with Coumadin Therapy?

  • Food: Vegetables such as broccoli, collard greens, and spinach, are rich in vitamin K. These can cancel out the effects of Coumadin. We want you to eat healthy foods, but it is important to consume approximately the same amount of these foods on a daily/weekly basis. For example: If you usually do not eat leafy green vegetables, but decide to “eat healthy” and suddenly consume a lot of these types of foods, it can counteract the effects of Coumadin and cause your blood to clot more easily. Your lab tests help us to adjust your Coumadin dosage, so consistent diet helps by not causing unusual spikes or drops in your INR lab value.
  • Alcohol: We do not promote the use of alcohol with this drug; however, if you drink we ask that you limit your alcohol intake to 1 or 2 drinks each day.
  • Drugs: Please tell us about any medication changes, new drugs or drugs that your doctor has told you to stop taking. Drugs such as antibiotics, cholesterol and pain medications are especially important to us. Please let us know if you start or stop any of these medications. It is also important to let us know if you are taking any over the counter medications and/or herbal supplements (ginseng, ginkgo, kava, etc.) as some can interfere with Coumadin.

What lab tests will I need?

When you come to the clinic you will have a blood test called an INR (International Normalized Ratio). This checks your clotting times and we may adjust your dose of Coumadin based on this result. Low INR increases the risk of clots forming which can cause strokes, clots in the lungs (Pulmonary Embolism) and deep vein thrombosis (DVT). High INR levels cause you to be at risk of bleeding. This is why it is important to consistently monitor INR levels, so that adjustments can be made if necessary.

Online Medical Reviewer: Louise Akin, RN, BSN
Online Medical Reviewer: Daphne Pierce-Smith, RN, MSN, FNP, CCRC
Date Last Reviewed: 7/9/2014
© 2000-2015 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.